Pb0.8Sn0.2Se thin films: synthesis, sensitization, and properties evolution

• Published in: Journal of materials science. Materials in electronics Vol. 33; no. 8; pp. 5564 - 5574
• Main Authors: Li, Zhen, Chen, Yingying, Lang, Haoze, Wan, Jianghong, Gao, Yan, Dong, Haitao, Zhang, Xiaoke, Feng, Wenran
• Format: Journal Article
• Language: English
• Published: New York Springer US 01-03-2022; Springer Nature B.V
• Subjects: Characterization and Evaluation of Materials; Chemistry and Materials Science; Crystal structure; Density of states; Energy gap; Energy levels; First principles; Iodine; Lead selenides; Materials Science; Mathematical analysis; Optical and Electronic Materials; Photoelectricity; Preferred orientation; Sensitivity enhancement; Thin films
• ISSN: 0957-4522; 1573-482X
• DOI: 10.1007/s10854-022-07744-6

The ternary Pb–SnSe thin films were prepared using chemical bath deposition (CBD) and sensitized with iodine. The chemical formula of the films was recognized as Pb
0.8
Sn
0.2
Se, according to the stoichiometric ratio. The films are both centered cubic crystal structure and show preferred orientation in PbSe (200). The optical band gap (
E
g
) is found to decrease after sensitization, due to the impurity energy levels created by PbI
2
. The photoelectric performance of the Pb
0.8
Sn
0.2
Se thin films is significantly improved after iodine sensitization. Accordingly, the resistance change rate, i.e., the photoelectric sensitivity is enhanced over 35%, which is over 161% for more than 4 on/off cycles. The density of states (DOS) of Pb
0.8
Sn
0.2
Se is calculated using the first-principle method. The calculation shows that the
I
dangling bond in sensitized Pb
0.8
Sn
0.2
Se introduces a large DOS inside the band gap and causes the narrowing of the band gap.